Week 1- Cell Met I

Question 1

What are the 6 types of metabolic reaction & describe them

Answer 1

Ligation requiring ATP cleavage- forming covalent bonds
Oxidation/reduction- electron transfer
Isomerisation- rearrangement of molecules
Functional group transfer- functional group from one molecule to another
Hydrolysis- breakdown using water
Addition/removal of functional group- making or breaking a double bond

Question 2

Overall, what happens in glycolysis?

Answer 2

One molecule of glucose (6C) is converted to 2 molecules of pyruvate (3C) in 2 stages: the formation of a high energy compound, and the breakdown of that high energy compound, overall net gain of 2 ATP and 2 NADH

Question 3

Describe the 1st step of glycolysis

Answer 3

Glucose goes to glucose 6 phosphate vis enzyme hexokinase, one molecule of ATP used and converted to ADP (group transfer reaction)

Question 4

Describe the 2nd step of glycolysis

Answer 4

Glucose 6 phosphate converted to fructose 6 phosphate via enzyme phosphoglucose isomerase (isomerisation reaction)

Question 5

Describe the 3rd step of glycolysis

Answer 5

Fructose 6 phosphate is converted to fructose 1,6 bisphosphate via phosphofructokinase whilst one ATP is used and converted to ADP (group transfer reaction)

Question 6

Describe the 4th step of glycolysis

Answer 6

Fructose 1,6 bisphosphate is converted to glyceraldehyde 3 phosphate and dihydroxyacetone phosphate via enzyme adolase (high energy compounds) in a hydrolysis reaction

Question 7

Describe the 5th step of glycolysis

Answer 7

Dihydroxyacetone phosphate is converted to glyceraldehyde 3 phosphate via TPI in an isomerisation reaction

Question 8

Describe the 6th step of glycolysis

Answer 8

2x glyceraldehyde 3 phosphate is converted to 1,3, bisphosphoglycerate via glyceraldehyde 3 phosphate dehydrogenase, one molecule fo NADH is produced

Question 9

Describe the 7th step of glycolysis

Answer 9

1,3 bisphosphoglycerate is converted to 3 phosphoglycerate via phosphoglycerate kinase, on molecule of ATP is formed (group transfer reaction)

Question 10

Describe the 8th step of glycolysis

Answer 10

3 phosphoglycerate is converted to 2 phosphoglycerate by phosphoglycerate mutase in an isomerisation reaction

Question 11

Describe the 9th step of glycolysis

Answer 11

2 phosphoglycerate is converted to phosphopenol pyruvate and water via enolase enzyme (dehydration and group removal reaction)

Question 12

Describe the 10th step of glycolysis

Answer 12

Phosphophenol pyruvate is converted to pyruvate via pyruvate kinase in a group transfer reaction. One molecule of ATP is produced

Question 13

What are the 3 fates of pyruvate?

Answer 13

Alcoholic fermentation, generation of lactate, generation of acetyl coA (all with common aim of producing NADH to allow glycolysis to continue)

Question 14

Describe alcoholic fermentation

Answer 14

Pyruvate goes to acetaldehyde via pyruvate decarboxylase then acetaldehyde goes to ethanol via ethanol dehydrogenase. Occurs in yeast and in anaerobic conditions

Question 15

Describe lactate generation

Answer 15

Pyruvate goes to lactate via lactate dehydrogenase

Question 16

Describe acetyl coA generation

Answer 16

Pyruvate and hs-coA goes to acetyl coA and co2 via pyruvate dehydrogenase complex, one molecule of NADH is produced

Question 17

Describe the Krebs cycle

Answer 17

CoA, isocitrate, ketoglutarate, succinyl coA, succincte, fumerate, malade, oxaloacetate (can I keep selling sex for money officer) net gain 3 NADH, 2 co2, 1 GTP, 1 FADH2

Question 18

How are proteins metabolized?

Answer 18

Transamination- the amino group is removed and added to a keto acid creating a new amino acid and keto acid (one of which can be pyruvate

Question 19

What are the 2 ways NADH produced in glycolysis enters the mitochondria to be used in oxidative phosphorylation

Answer 19

Malate aspartame shuttle or glycerol phosphate shuttle

Question 20

Describe the glycerol phosphate shuttle

Answer 20

Cytosolic glycerol 3 phosphate dehydrogenase transfers electrons from NADH to DHAP. A membrane bound version of the enzyme then transfers the electrons to FAD, these pass onto coenzyme Q (part of the ETC)

Question 21

Describe the malate aspartate shuttle

Answer 21

Oxaloacetate is converted to malate via malate dehydrogenase (one molecule of NADH used and converted to NAD) in the inter-membrane space. This malate molecule is carried in to the matrix by the malate/alpha ketoglutarate carrier. The malate is converted to oxaloacetate in the matrix via same enzyme. This is then converted to aspartate via aspartate aminotranferase and aspartate is carried out to the inter mem space via glutamate aspartate carrier. Every time this happens one molecule of glutamate is pumped in to the matrix from inter mem space. Glutamate is converted to alpha ketoglutarate via aspartate aminotansferase in the matrix, and every time a molecule of malate enters the matrix one molecule of alpha ketoglutarate is pumped out into the inter mem space. In the inter mem space aspartate aminotransferase converts aspartate back to oxalocatate so the cycle can restart

Question 22

What 5 molecules are involved in the malate aspartate shuttle?

Answer 22

Oxaloacetate, malate, aspartate, glutamate, alpha ketoglutarate

Question 23

What are the 2 antiporters in the malate aspartate shuttle?

Answer 23

Malate/alpha ketoglutarate

Glutamate/aspartate

Question 24

What are the 2 enzymes in the malate aspartate shuttle?

Answer 24

Malate dehydrogenase

Aspartate aminotransferase

Question 25

How does glucose metabolism often differ in cancer?

Answer 25

Cancer cells have a higher no of glucose transporters so they can be radio-labelled and the location of them can be mapped